MACFLINCOR AND ITS APPLICATION TO FLUIDS IN ARCHEAN LODE-GOLD DEPOSITS

Abstract

MacFlinCor was developed to process laboratory data gathered on fluid inclusions and to calculate isochores for geologically important fluids composed of H2O, CO2, CH4, NaCl, and N2. Within the program, interactive diagrams are available to describe those chemical systems which cannot be adequately constrained numerically. The user can choose from various published equations of state describing fluid behavior and can easily compare the results obtained by using different equations.The program, once the basic fluid parameters have been established, allows the data to be used to determine the P-T trapping conditions, to evaluate possible pressure corrections and to compare different depths of formation based on the pressure calculations and given geothermal gradients.For illustrative purposes, MacFlinCor has been utilized here to constrain different physical-chemical parameters of fluid inclusions trapped in ore-related quartz veins and breccias of Archean lode-gold deposits in Western Australia. Inferred pressures from individual deposits show a wide range of values which may be due to post-entrapment modifications and/or observational uncertainties including estimation of liquid-vapor ratios.